The purpose of this study is to determine the effectiveness and acceptance of an "alternative diet" by a random sample of 233 families in Portland, Oregon. Dietary change will be induced in free living family units. The proposed diet is known to produce maximal lowering of increased plasma cholesterol and lipoprotein levels. We plan to use a phased approach to dietary change which will produce a modification of dietary style that, at its fullest expression, is far removed from the conventional American diet, but is similar to diets historically consumed by man. The "alternative diet" is low in cholesterol, saturated fat, total fat and sodium and contains increased amounts of complex carbohydrate, fiber and potassium. It is nutritionally adequate. The primary technique used to change eating behavior will be group discussions using methods which have demonstrated effectiveness in behavioral change of appetitive habits (awareness of eating behavior, environmental control, modeling of appropriate eating behavior, increasing the social desirability of the diet, and utilization of group process and dynamics). Printed media and new recipes will also be used to help in dietary change and to prevent backsliding. The extent to which this program is effective in influencing the members of these families in making changes in their eating behavior will be measured by certain end-points: plasma lipids and lipoproteins, dietary histories and evaluation of the study population to determine acceptance, rejection and adherence of the diet, and the distinguishing characteristics of people and families who change as contrasted to those who do not change. Unique aspects of this proposal are the focus on family unit, a gradual, non-coercive and positive motivational approach, and the test of the "alternative diet" which is compatible with a total nutritional approach to the prevention of diseases of overconsumption including coronary heart disease and hypertension.